Exploration tendency, one of the most investigated animal personality traits, may be driven by either positive (when seeking interesting information) or negative (to reduce the uncertainty of the environment) affective/emotional profiles. To disentangle the valence of the affective state associated with exploration trait, we applied a judgment bias test to evaluate the animals’ responses in an ambiguous situation, allowing an assessment of their affective state or mood. Experiments were carried out in male house mice (Mus musculus) of wild origin. Individual differences in exploration tendency were assessed by repeated open field and novel object tests. To evaluate the animals’ judgment bias, we trained the subjects for 8 days in a 3-arm maze to discriminate between two extreme locations (outer arms: either positively reinforced with sugary water or less-positively reinforced with plain water), in terms of a shorter latency to approach the positively reinforced arm. After this learning criterion was reached, we repeatedly tested their responses to an ambiguous location (intermediate arm). The latencies to approach and consume the ambiguous reward were highly repeatable over the 3 days of testing; hence individuals expressed a stable judgment bias. Most importantly, more exploratory animals showed a more negative judgment bias, which supports the hypothesis that a higher exploration tendency was associated with a negative affective state. Further studies should investigate whether exploration in different situations might be due to distinct affective states.

探索趋势是研究最多的动物人格特质之一，可能由积极的（在寻找有趣的信息时）或消极的（以减少环境的不确定性）的情感/情感特征所驱动。为了弄清与探索性状相关的情感状态的价，我们应用了判断偏差测试来评估动物在歧义情况下的反应，从而评估它们的情感状态或情绪。实验是在雄性家鼠（小家鼠）中进行的）的野生来源。勘探趋势的个体差异通过反复的野外测试和新颖的物体测试进行评估。为了评估动物的判断偏见，我们在3臂迷宫中对受试者进行了8天的训练，以区分两个极端位置（外臂：用含糖水积极增强，或用白水增强弱势），接近积极加强手臂的等待时间较短。达到此学习标准后，我们​​反复测试了他们对歧义位置（中间手臂）的反应。在测试的三天内，接近和消耗模棱两可的奖励的延迟是高度可重复的；因此，个人表现出稳定的判断偏见。最重要的是，更多探索性动物表现出更大的负面判断偏见，这支持了较高的探索倾向与负面情感状态相关的假设。进一步的研究应调查在不同情况下的探索是否可能是由于不同的情感状态引起的。